PVF₂ catheter-tip transducers for pressure, sound and flow measurements

Abstract

Several possible configurations of ferroelectric polymer catheter-tip sensors for the detection of intracavitary pressure and sound are compared on the basis of calculated free-field voltage sensitivity. The design, construction and testing of a polyvinylidene fluoride (PVF₂) catheter-tip transducer operating primarily in the extensional mode is described in detail. Compared in vitro with a commercial silicon strain-gauge microtransducer, the PVF₂ sensor showed remarkable capability to detect faithfully pressure waveforms and sounds. Preliminary tests also demonstrated its ability to record, via the pyroelectric effect, thermal indicator dilution curves which compare well with those provided by a commercial thermistor catheter. In vivo experiments confirm the effectiveness of the PVF₂ sensor. The major limitation of the ferroelectric devices is the lack of DC response, which makes them generally unable to measure static values of the parameters of interest.